NASA Launching High-Tech Inflatable Heat Shield Test Saturday

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When you think of the blistering, brutal re-entry temperatures
generated by plowing through Earth’s atmosphere, using fabric
doesn’t come quickly to mind.

But NASA is set to try some fabric out this Saturday (July 21),
as part of a novel
inflatable re-entry experiment that could find a variety of
uses, both off planet and possibly in returning payloads from the
International Space Station as well.

The Inflatable Re-entry Vehicle Experiment III, or IRVE-3, has
been years in the making for all of 20 minutes of suborbital
flight. It will be rocketed to high altitude above Earth from
NASA’s Wallops Flight Facility near Chincoteague Island, Va.,
then will dive into the Atlantic Ocean.

It’s all “science friction” — pushing the envelope, quite
literally, while trying to beat the heat of
atmospheric re-entry.

The uninflated IRVE-3 is carefully stuffed into a flight bag that
fits inside the rocket’s nose cone. Once IRVE-3 is released at
its target altitude, its high-tech inner tubes will be inflated
by nitrogen to give the
experimental heat shield a mushroom shape.

The ready-for-re-entry contour is made of layers of
silicone-coated industrial fabric. As the tubes are inflated,
they stretch out a thermal blanket covering them to create a heat
shield known as an aeroshell.

During re-entry, video cameras will transmit images to the
Wallops control room to confirm that the IRVE-3 is holding up
during its heat-defying trek. Instruments on board will also
transmit temperature and pressure data to researchers for later
analysis.

A rigorous ground test program of IRVE-3’s thermal protection
system has already been performed using a number of facilities,
Cheatwood told SPACE.com. But the upcoming flight will use
the Earth’s atmosphere as an ultimate test.

IRVE-3 will be lobbed some 350 miles (560 kilometers) downrange
into Atlantic Ocean waters.

A game- changing technology

NASA’s Office of the Chief Technologist (OCT) is behind the
Hypersonic Inflatable Aerodynamic Decelerator (HIAD) project,
under which the IRVE-3 experiment is being carried out. IRVE work
is one venture within the office's OCT’s Game Changing
Development program for new space technologies.

Testing of the IRVE over the years has seen both malfunction and
success. A booster failure cut short its first flight in
September 2007.

"The original Inflatable Re-entry Vehicle Experiment was designed
to demonstrate that inflatable structures could inflate, remain
inflated, and maintain stability," said Kathy Barnstorff, a
Langley center spokeswoman for the project. "However, IRVE
encountered a failure after launch in which the IRVE instrument
was unable to separate from the metal payload cylinder
surrounding it."

Building on success

In August 2009, IRVE scored its first success. Riding on a Black
Brant 9 rocket, the booster reached a high point of 131 miles
(211 km), where it began its descent to supersonic speed. Less
than a minute later the
IRVE-2 was released to inflate in less than 90 seconds at an
altitude of 124 miles (200 km).

Cheatwood recalls that the 2009 flight verified the IRVE was
stable when it was inflated to its profile. It behaved like a
rigid blunt body of the same shape, he said, making it through
the heat pulse.

"The experiment really was … just to take us through the heat
pulse. It was like a 30-second experiment, officially," Cheatwood
added. "It flew right through supersonic, transonic, into
subsonic."

IRVE-3 is the same size — nearly 10 feet wide (3 meters)
when inflated — as the other two.

"IRVE-3 is launching on a larger rocket which will take it to a
higher altitude," Barnstorff told SPACE.com. "It will come back
in with a higher velocity and more heating than IRVE-2 saw.
IRVE-3 will see about 10 times the heating that IRVE-2 did. It’s
a heavier payload, which also contributes to the higher heat
levels."

Using atmospheres on other worlds

Cheatwood said that work is ongoing in thermal protection
materials that can take even greater heat loads. "That would let
us handle higher heat rates, which means we could be smaller in
diameter," he said.

HIAD-inspired technology is seen as ideal for use on NASA
missions, be they to Mars, Venus or even Titan — the largest moon
of Saturn. For example, far more precise landings on the Red
Planet of robotic craft on the Red Planet are feasible. But the
technology is envisioned to be scalable for piloted expeditions
to Mars, too.

Adopting inflatable heat shields could lead to landing more mass
on Mars at higher surface elevations. The larger the diameter of
a protective aeroshell, the bigger the payload can be.

The HIAD work can also be applied to Earth-returning payloads let
loose from the International Space Station.

Already being sketched out is the High Energy Atmospheric
Re-entry Test (HEART) — a design concept for a flight test
that would utilize larger inflatable re-entry technology with a
diameter of almost 30 feet (8 meters).

Here’s the bottom line for Cheatwood: "If a planet has an
atmosphere … we can use it."

Leonard David has been reporting on the space industry for
more than five decades. He is a winner of last year's National
Space Club Press Award and a past editor-in-chief of the National
Space Society's Ad Astra and Space World magazines. He has
written for SPACE.com since 1999.